nfsd: Change the type of ek_fsidtype from int to u8 and use kstrtou8

The valid values for ek_fsidtype are actually 0-7 so it's better to
change the type to u8. Also using kstrtou8() to relpace simple_strtoul(),
kstrtou8() is safer and more suitable for u8.

Suggested-by: NeilBrown <neil@brown.name>
Signed-off-by: Su Hui <suhui@nfschina.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Author: Su Hui

fs/nfsd/export.c

@@ -82,8 +82,7 @@ static int expkey_parse(struct cache_detail *cd, char *mesg, int mlen)
 	int len;
 	struct auth_domain *dom = NULL;
 	int err;
-	int fsidtype;
-	char *ep;
+	u8 fsidtype;
 	struct svc_expkey key;
 	struct svc_expkey *ek = NULL;
 
@@ -109,10 +108,9 @@ static int expkey_parse(struct cache_detail *cd, char *mesg, int mlen)
 	err = -EINVAL;
 	if (qword_get(&mesg, buf, PAGE_SIZE) <= 0)
 		goto out;
-	fsidtype = simple_strtoul(buf, &ep, 10);
-	if (*ep)
+	if (kstrtou8(buf, 10, &fsidtype))
 		goto out;
-	dprintk("found fsidtype %d\n", fsidtype);
+	dprintk("found fsidtype %u\n", fsidtype);
 	if (key_len(fsidtype)==0) /* invalid type */
 		goto out;
 	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)

fs/nfsd/export.h

@@ -88,7 +88,7 @@ struct svc_expkey {
 	struct cache_head	h;
 
 	struct auth_domain *	ek_client;
-	int			ek_fsidtype;
+	u8			ek_fsidtype;
 	u32			ek_fsid[6];
 
 	struct path		ek_path;

fs/nfsd/trace.h

@@ -344,7 +344,7 @@ TRACE_EVENT(nfsd_exp_find_key,
 		 int status),
 	TP_ARGS(key, status),
 	TP_STRUCT__entry(
-		__field(int, fsidtype)
+		__field(u8, fsidtype)
 		__array(u32, fsid, 6)
 		__string(auth_domain, key->ek_client->name)
 		__field(int, status)
@@ -367,7 +367,7 @@ TRACE_EVENT(nfsd_expkey_update,
 	TP_PROTO(const struct svc_expkey *key, const char *exp_path),
 	TP_ARGS(key, exp_path),
 	TP_STRUCT__entry(
-		__field(int, fsidtype)
+		__field(u8, fsidtype)
 		__array(u32, fsid, 6)
 		__string(auth_domain, key->ek_client->name)
 		__string(path, exp_path)